Sodium MRI is sensitive to proteoglycan loss in
cartilage. The goals of this study were twofold: to attempt to identify any
age-related change of sodium signal in the knee cartilage, and to assess the
repeatability of sodium signal measurements in cartilage at two time points.
Fifteen subjects (ages 21 to 48 years) were scanned using sodium MRI. This
relatively young population did not show age-dependent change in cartilage sodium
signal but their medial tibiofemoral cartilage had significantly higher sodium
signal than other regions. The average variability of the cartilage sodium
signal within 48 hours was 6.6%.